Gas sealing box construction for heat treatment and the like



W. HOWELL GAS SEALING BOX CONSTRUCTION FOR HEAT TREATMENT AND THE LIKE Filed June 14, 1957 2 Sheets-Sheet 1 M'lll'amflolwll w, MW

May 17, 1938.

GAS SEALING w. HOWELL 2,117,423

BOX CONSTRUCTION FOR HEAT TREATMENT AND THE LIKE Filed June 14, 1957 2 Sheets-Sheet 2 Fig.2 m'llmmwwlz Patented May 17, 1938 UNITED STATES GAS SEALING BOX CONSTRUCTION FOR HEAT TREATMENT AND THE LIKE William Howell, Warren, Ohio Application June 14, 1937, Serial No. 148,097

teatime.

The invention relates to gas sealing box construction for heat treatment of metal and the like and more particularly to controlled atmosphere box annealing.

Annealing furnaces of a present preferred type include a box furnace having a lower opening which is arranged for gas sealing association with a furnace bottom, upon which is supported the material being annealed, usually a stack of steel sheets. The stack' of sheets are also covered by a downwardly opening metal annealing box.

Present practice in heat treating for example in annealing, utilizes a controlled atmosphere about the stack of material being annealed within the inner box, and for example it is desirable in annealing to maintain a pressure of 3 inches of water in a special deoxidizing atmosphere within the inner annealing box.

After the outer furnace box has been operated for a sufficient time, it is removed and the inner box with the material being heat treated is then slowly cooled off, in annealing for exampie for a period of 72 hours, during which time it is necessary to maintain the pressure of the preferred special atmosphere within the inner' box about the material being heat treated.

Prior to the present improvements, great difficulties were encountered in maintaining a gas seal between the inner box and the furnace bottom.

One arrangement in use prior to the present improvements included a separate met-a1 pan having upturned edges, which rested upon the furnace bottom and upon which heat resistant material such as brick were placed, and also upon which the lower edges of the inner box rested.

These separate metal gas sealing pans warped in use and required frequent replacement, thereby creating a relatively high maintenance cost.

When the separate metal gas sealing pan for the inner box has not been used, and the inner box has rested directly upon the heat resistant material such as brick covering the furnace bottom, leakage has occurred of the special atmosphere desired to. be retained at a specified pressure within the inner box after the removal of the box furnace.

The objects of the present improvements include the provision of improved gas sealing box construction for the inner box of a downwardly opening box heat treating furnace, and which eliminates the necessity of using a separate metal gas sealing pan for the inner box and which also maintains the pressure of a controlled atmosphere within the 'inner box after the outer box furnace has been removed.

The foregoing and other objects are attained by the improved gas sealing box construction, parts, combinations and sub-combinations which 5 comprise the present invention, and the nature of which is set forth in the following general statement, and preferred embodiments of which together with their mode of use are set forth in the following description, and which are particularly and distinctly pointed out and set forth in the appended claims forming part hereof.

The nature of the present invention may be described in general terms as including preferably in heat treating furnace construction, a metal bottom plate having a heat resistant covering material thereupon, outer gas sealing means, a removable downwardly opening. box furnace having lower members adapted for gas sealing interfitting with the outer gas sealing means of the bottom plate, inner metal gas sealing members extending from the bottom plate and having their sides protected by the covering material and having upper gas sealing faces, and a downwardly opening metal box having sides, the lower 25 edges of which removably seat upon the gas sealing faces of the metal gas sealing members of the bottom plate. a

By way of example preferred embodiments of the improvements hereof are illustrated in the 30 accompanying drawings forming part hereof, in which Figure 1 is a transverse sectional view illustrating a downwardly opening heat treating furnace in place on one of the improved bottoms of the present invention and over the inner box enclosing a stack of steel sheets, the bottom and the inner box being provided with one embodiment of the gas sealing improvements hereof;

Fig. 2, a view similar to Fig. 1 with the outer furnace removed;

Fig. 3, a top plan View of the improved furnace and box bottom of Figs. 1 and 2; and Fig. 4, a fragmentary view similar to Fig. 2 illustrating a modified embodiment of the improved gas sealing box construction hereof.

Similar numerals refer to similar parts throughout the drawings.

In Figs. 1, 2 and 3, one embodiment of the improved gas sealing box construction of the present invention is illustrated and indicated generally by ID, and includes afurnace and box bottom ll, having a metal bottom plate I! with outer gas sealing means indicated generally by l3 of usual construction for association with the lower portions of a removable downwardly opening furnace M.

The metal furnace and box bottom plate 02 is provided with heat resisting covering material 15 which may be brick-work, and metal gas sealing members i8 extend upwardly from the furnace bottom plate i2 and have upper gas sealing faces I! as shown at the upper level of the heat resisting covering material 45. The metal gas sealing members 56 are preferably end connected with each other.

A metal downwardly opening inner box it includes sides, the lower edges 89 of which removably seat upon the upper gas sealing faces ll of the metal gas sealing members i 6.

Means providing a granular, preferably sand, seal about the metal box edges l9 seated upon the gas sealing faces ll of the metal bottom plate gas sealing members l6 are preferably provided and may include upwardlyextending bricks 20 outwardly spaced from the gas sealing members l6 and sand 2i interposed between the brick 2b and the sides of the inner box it.

As shown a stack of steel sheets 22 is located within the inner box H3.

The furnace as shown in Fig. l is brought to the desired heat and maintained at such heat according to standard practice, after which the furnace box M is removed leaving the inner box and the furnace and box bottom H as shown in Fig. 2.

The present improvements provide an eifective gas seal between the bottom M and the inner box 18, and the metal gas sealing members of the bottom II are protected by the heat resistant material IS.

The improved gas sealing box construction as shown is operative so that a special atmosphere within the inner box I 8 may be maintained for example for a period of 72 hours without leakage.

The modified form of the invention shown in Fig. 4 includes gas sealing members H6 integrally formed in the bottom plate H2.

The embodiments of the improved gas sealing box construction illustrated and described herein attain the above stated objects of the invention, but are by way of example, and the scope of the present invention is not limited to the same or to the particular details thereof, but is commensurate with any and all novel subject matter contained herein, and which may at any time properly under the patent laws be set forth in claims hereof or which may originate herein, the elements of any of the claims being intended to include their reasonable equivalents.

I claim:

1. In gas sealing box construction for heat treating and the like, a metal bottom plate, heat resistant covering material upon the bottom plate, inner metal gas sealing members extending from the bottom plate and having their sides protected by the covering material and having upper gas sealing faces, and outer gas sealing means on the bottom plate about the inner metal gas sealing members, the inner metal gas sealing members being adapted for gas sealing the lower edges of a downwardly opening metal box seated thereupon, and the outer gas sealing means being adapted for gas sealing the lower portions of a. downwardly opening box furnace.

2. In gassealing box construction for heat treating and the like, a metal bottom plate, heat resistant covering material upon the bottom plate, inner metal gas sealing members extending from the bottom plate and having their sides protected by the covering material and having upper gas sealing faces, and outer gas sealing means on the bottom plate about the inner metal gas sealing members, the inner metal gas sealing members being adapted for gas sealing the lower edges of a downwardly opening metal box seated thereupon, and the outer gas sealing means being adapted for gas sealing the lower portions of a downwardly opening box furnace, and means for providing a granular seal associated with the gas sealing faces of the inner metal gas sealing members and metal box edges seated thereupon.

3. In heat treating furnace construction, a metal bottom plate, heat resistant covering material upon the bottom plate, outer gas sealing means, a removable downwardly opening box furnace having lower members adapted for gas sealing interfitting with the outer gas sealing means of the bottom plate, inner metal gas sealing members extending from the bottom plate and having their sides protected by the covering material and having upper gas sealing faces, and a downwardly opening metal box having sides the lower edges of which removably seat upon the gas sealing faces of the metal gas sealing members of the bottom plate.

4. In heat treating furnace construction, a metal bottom plate, heat resistant covering material upon the bottom plate, outer gas sealing means, a removable downwardly opening box furnace having lower members adapted for gas sealing interfitting with the outer gas sealing means of the bottom plate, inner metal gas sealing members extending from the bottom plate and having their sides protected by the covering material and having upper gas sealing faces, and a downwardly opening metal box having sides the lower edges of which removably seat upon the gas sealing faces of the metal gas sealing members of the bottom plate, and means providing a granular seal about the metal box edges seated upon the gas sealing faces of the metal bottom plate gas sealing members.

WILLIAM HOWELL. 

